1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- E X P A N D E R -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2019, Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING3. If not, go to -- 19-- http://www.gnu.org/licenses for a complete copy of the license. -- 20-- -- 21-- GNAT was originally developed by the GNAT team at New York University. -- 22-- Extensive contributions were provided by Ada Core Technologies Inc. -- 23-- -- 24------------------------------------------------------------------------------ 25 26with Atree; use Atree; 27with Debug; use Debug; 28with Debug_A; use Debug_A; 29with Exp_Aggr; use Exp_Aggr; 30with Exp_SPARK; use Exp_SPARK; 31with Exp_Attr; use Exp_Attr; 32with Exp_Ch2; use Exp_Ch2; 33with Exp_Ch3; use Exp_Ch3; 34with Exp_Ch4; use Exp_Ch4; 35with Exp_Ch5; use Exp_Ch5; 36with Exp_Ch6; use Exp_Ch6; 37with Exp_Ch7; use Exp_Ch7; 38with Exp_Ch8; use Exp_Ch8; 39with Exp_Ch9; use Exp_Ch9; 40with Exp_Ch11; use Exp_Ch11; 41with Exp_Ch12; use Exp_Ch12; 42with Exp_Ch13; use Exp_Ch13; 43with Exp_Prag; use Exp_Prag; 44with Ghost; use Ghost; 45with Opt; use Opt; 46with Rtsfind; use Rtsfind; 47with Sem; use Sem; 48with Sem_Ch8; use Sem_Ch8; 49with Sem_Util; use Sem_Util; 50with Sinfo; use Sinfo; 51with Table; 52 53package body Expander is 54 55 ---------------- 56 -- Local Data -- 57 ---------------- 58 59 -- The following table is used to save values of the Expander_Active flag 60 -- when they are saved by Expander_Mode_Save_And_Set. We use an extendible 61 -- table (which is a bit of overkill) because it is easier than figuring 62 -- out a maximum value or bothering with range checks. 63 64 package Expander_Flags is new Table.Table ( 65 Table_Component_Type => Boolean, 66 Table_Index_Type => Int, 67 Table_Low_Bound => 0, 68 Table_Initial => 32, 69 Table_Increment => 200, 70 Table_Name => "Expander_Flags"); 71 72 Abort_Bug_Box_Error : exception; 73 -- Arbitrary exception to raise for implementation of -gnatd.B. See "when 74 -- N_Abort_Statement" below. See also debug.adb. 75 76 ------------ 77 -- Expand -- 78 ------------ 79 80 -- WARNING: This routine manages Ghost regions. Return statements must be 81 -- replaced by gotos which jump to the end of the routine and restore the 82 -- Ghost mode. 83 84 procedure Expand (N : Node_Id) is 85 Saved_GM : constant Ghost_Mode_Type := Ghost_Mode; 86 Saved_IGR : constant Node_Id := Ignored_Ghost_Region; 87 -- Save the Ghost-related attributes to restore on exit 88 89 begin 90 -- If we were analyzing a default expression (or other spec expression) 91 -- the Full_Analysis flag must be off. If we are in expansion mode then 92 -- we must be performing a full analysis. If we are analyzing a generic 93 -- then Expansion must be off. 94 95 pragma Assert 96 (not (Full_Analysis and then In_Spec_Expression) 97 and then (Full_Analysis or else not Expander_Active) 98 and then not (Inside_A_Generic and then Expander_Active)); 99 100 -- Establish the Ghost mode of the context to ensure that any generated 101 -- nodes during expansion are marked as Ghost. 102 103 Set_Ghost_Mode (N); 104 105 -- The GNATprove_Mode flag indicates that a light expansion for formal 106 -- verification should be used. This expansion is never done inside 107 -- generics, because otherwise, this breaks the name resolution 108 -- mechanism for generic instances. 109 110 if GNATprove_Mode then 111 if not Inside_A_Generic then 112 Expand_SPARK (N); 113 end if; 114 115 Set_Analyzed (N, Full_Analysis); 116 117 -- Regular expansion is normally followed by special handling for 118 -- transient scopes for unconstrained results, etc. but this is not 119 -- needed, and in general cannot be done correctly, in this mode, so 120 -- we are all done. 121 122 goto Leave; 123 124 -- There are three reasons for the Expander_Active flag to be false 125 126 -- The first is when are not generating code. In this mode the 127 -- Full_Analysis flag indicates whether we are performing a complete 128 -- analysis, in which case Full_Analysis = True or a preanalysis in 129 -- which case Full_Analysis = False. See the spec of Sem for more info 130 -- on this. 131 132 -- The second reason for the Expander_Active flag to be False is that 133 -- we are performing a preanalysis. During preanalysis all expansion 134 -- activity is turned off to make sure nodes are semantically decorated 135 -- but no extra nodes are generated. This is for instance needed for 136 -- the first pass of aggregate semantic processing. Note that in this 137 -- case the Full_Analysis flag is set to False because the node will 138 -- subsequently be re-analyzed with expansion on (see the spec of sem). 139 140 -- Finally, expansion is turned off in a regular compilation if there 141 -- are serious errors. In that case there will be no further expansion, 142 -- but one cleanup action may be required: if a transient scope was 143 -- created (e.g. for a function that returns an unconstrained type) the 144 -- scope may still be on the stack, and must be removed explicitly, 145 -- given that the expansion actions that would normally process it will 146 -- not take place. This prevents cascaded errors due to stack mismatch. 147 148 elsif not Expander_Active then 149 Set_Analyzed (N, Full_Analysis); 150 151 if Serious_Errors_Detected > 0 and then Scope_Is_Transient then 152 Scope_Stack.Table 153 (Scope_Stack.Last).Actions_To_Be_Wrapped := (others => No_List); 154 Pop_Scope; 155 end if; 156 157 goto Leave; 158 159 else 160 begin 161 Debug_A_Entry ("expanding ", N); 162 163 -- Processing depends on node kind. For full details on the 164 -- expansion activity required in each case, see bodies of 165 -- corresponding expand routines. 166 167 case Nkind (N) is 168 when N_Abort_Statement => 169 Expand_N_Abort_Statement (N); 170 171 -- If -gnatd.B switch was given, crash the compiler. See 172 -- debug.adb for explanation. 173 174 if Debug_Flag_Dot_BB then 175 raise Abort_Bug_Box_Error; 176 end if; 177 178 when N_Accept_Statement => 179 Expand_N_Accept_Statement (N); 180 181 when N_Aggregate => 182 Expand_N_Aggregate (N); 183 184 when N_Allocator => 185 Expand_N_Allocator (N); 186 187 when N_And_Then => 188 Expand_N_And_Then (N); 189 190 when N_Assignment_Statement => 191 Expand_N_Assignment_Statement (N); 192 193 when N_Asynchronous_Select => 194 Expand_N_Asynchronous_Select (N); 195 196 when N_Attribute_Definition_Clause => 197 Expand_N_Attribute_Definition_Clause (N); 198 199 when N_Attribute_Reference => 200 Expand_N_Attribute_Reference (N); 201 202 when N_Block_Statement => 203 Expand_N_Block_Statement (N); 204 205 when N_Case_Expression => 206 Expand_N_Case_Expression (N); 207 208 when N_Case_Statement => 209 Expand_N_Case_Statement (N); 210 211 when N_Conditional_Entry_Call => 212 Expand_N_Conditional_Entry_Call (N); 213 214 when N_Delay_Relative_Statement => 215 Expand_N_Delay_Relative_Statement (N); 216 217 when N_Delay_Until_Statement => 218 Expand_N_Delay_Until_Statement (N); 219 220 when N_Delta_Aggregate => 221 Expand_N_Delta_Aggregate (N); 222 223 when N_Entry_Body => 224 Expand_N_Entry_Body (N); 225 226 when N_Entry_Call_Statement => 227 Expand_N_Entry_Call_Statement (N); 228 229 when N_Entry_Declaration => 230 Expand_N_Entry_Declaration (N); 231 232 when N_Exception_Declaration => 233 Expand_N_Exception_Declaration (N); 234 235 when N_Exception_Renaming_Declaration => 236 Expand_N_Exception_Renaming_Declaration (N); 237 238 when N_Exit_Statement => 239 Expand_N_Exit_Statement (N); 240 241 when N_Expanded_Name => 242 Expand_N_Expanded_Name (N); 243 244 when N_Explicit_Dereference => 245 Expand_N_Explicit_Dereference (N); 246 247 when N_Expression_With_Actions => 248 Expand_N_Expression_With_Actions (N); 249 250 when N_Extended_Return_Statement => 251 Expand_N_Extended_Return_Statement (N); 252 253 when N_Extension_Aggregate => 254 Expand_N_Extension_Aggregate (N); 255 256 when N_Free_Statement => 257 Expand_N_Free_Statement (N); 258 259 when N_Freeze_Entity => 260 Expand_N_Freeze_Entity (N); 261 262 when N_Full_Type_Declaration => 263 Expand_N_Full_Type_Declaration (N); 264 265 when N_Function_Call => 266 Expand_N_Function_Call (N); 267 268 when N_Generic_Instantiation => 269 Expand_N_Generic_Instantiation (N); 270 271 when N_Goto_Statement => 272 Expand_N_Goto_Statement (N); 273 274 when N_Handled_Sequence_Of_Statements => 275 Expand_N_Handled_Sequence_Of_Statements (N); 276 277 when N_Identifier => 278 Expand_N_Identifier (N); 279 280 when N_If_Expression => 281 Expand_N_If_Expression (N); 282 283 when N_Indexed_Component => 284 Expand_N_Indexed_Component (N); 285 286 when N_If_Statement => 287 Expand_N_If_Statement (N); 288 289 when N_In => 290 Expand_N_In (N); 291 292 when N_Loop_Statement => 293 Expand_N_Loop_Statement (N); 294 295 when N_Not_In => 296 Expand_N_Not_In (N); 297 298 when N_Null => 299 Expand_N_Null (N); 300 301 when N_Object_Declaration => 302 Expand_N_Object_Declaration (N); 303 304 when N_Object_Renaming_Declaration => 305 Expand_N_Object_Renaming_Declaration (N); 306 307 when N_Op_Add => 308 Expand_N_Op_Add (N); 309 310 when N_Op_Abs => 311 Expand_N_Op_Abs (N); 312 313 when N_Op_And => 314 Expand_N_Op_And (N); 315 316 when N_Op_Concat => 317 Expand_N_Op_Concat (N); 318 319 when N_Op_Divide => 320 Expand_N_Op_Divide (N); 321 322 when N_Op_Eq => 323 Expand_N_Op_Eq (N); 324 325 when N_Op_Expon => 326 Expand_N_Op_Expon (N); 327 328 when N_Op_Ge => 329 Expand_N_Op_Ge (N); 330 331 when N_Op_Gt => 332 Expand_N_Op_Gt (N); 333 334 when N_Op_Le => 335 Expand_N_Op_Le (N); 336 337 when N_Op_Lt => 338 Expand_N_Op_Lt (N); 339 340 when N_Op_Minus => 341 Expand_N_Op_Minus (N); 342 343 when N_Op_Mod => 344 Expand_N_Op_Mod (N); 345 346 when N_Op_Multiply => 347 Expand_N_Op_Multiply (N); 348 349 when N_Op_Ne => 350 Expand_N_Op_Ne (N); 351 352 when N_Op_Not => 353 Expand_N_Op_Not (N); 354 355 when N_Op_Or => 356 Expand_N_Op_Or (N); 357 358 when N_Op_Plus => 359 Expand_N_Op_Plus (N); 360 361 when N_Op_Rem => 362 Expand_N_Op_Rem (N); 363 364 when N_Op_Rotate_Left => 365 Expand_N_Op_Rotate_Left (N); 366 367 when N_Op_Rotate_Right => 368 Expand_N_Op_Rotate_Right (N); 369 370 when N_Op_Shift_Left => 371 Expand_N_Op_Shift_Left (N); 372 373 when N_Op_Shift_Right => 374 Expand_N_Op_Shift_Right (N); 375 376 when N_Op_Shift_Right_Arithmetic => 377 Expand_N_Op_Shift_Right_Arithmetic (N); 378 379 when N_Op_Subtract => 380 Expand_N_Op_Subtract (N); 381 382 when N_Op_Xor => 383 Expand_N_Op_Xor (N); 384 385 when N_Or_Else => 386 Expand_N_Or_Else (N); 387 388 when N_Package_Body => 389 Expand_N_Package_Body (N); 390 391 when N_Package_Declaration => 392 Expand_N_Package_Declaration (N); 393 394 when N_Package_Renaming_Declaration => 395 Expand_N_Package_Renaming_Declaration (N); 396 397 when N_Subprogram_Renaming_Declaration => 398 Expand_N_Subprogram_Renaming_Declaration (N); 399 400 when N_Pragma => 401 Expand_N_Pragma (N); 402 403 when N_Procedure_Call_Statement => 404 Expand_N_Procedure_Call_Statement (N); 405 406 when N_Protected_Type_Declaration => 407 Expand_N_Protected_Type_Declaration (N); 408 409 when N_Protected_Body => 410 Expand_N_Protected_Body (N); 411 412 when N_Qualified_Expression => 413 Expand_N_Qualified_Expression (N); 414 415 when N_Quantified_Expression => 416 Expand_N_Quantified_Expression (N); 417 418 when N_Raise_Statement => 419 Expand_N_Raise_Statement (N); 420 421 when N_Raise_Constraint_Error => 422 Expand_N_Raise_Constraint_Error (N); 423 424 when N_Raise_Expression => 425 Expand_N_Raise_Expression (N); 426 427 when N_Raise_Program_Error => 428 Expand_N_Raise_Program_Error (N); 429 430 when N_Raise_Storage_Error => 431 Expand_N_Raise_Storage_Error (N); 432 433 when N_Real_Literal => 434 Expand_N_Real_Literal (N); 435 436 when N_Record_Representation_Clause => 437 Expand_N_Record_Representation_Clause (N); 438 439 when N_Requeue_Statement => 440 Expand_N_Requeue_Statement (N); 441 442 when N_Simple_Return_Statement => 443 Expand_N_Simple_Return_Statement (N); 444 445 when N_Selected_Component => 446 Expand_N_Selected_Component (N); 447 448 when N_Selective_Accept => 449 Expand_N_Selective_Accept (N); 450 451 when N_Single_Protected_Declaration => 452 Expand_N_Single_Protected_Declaration (N); 453 454 when N_Single_Task_Declaration => 455 Expand_N_Single_Task_Declaration (N); 456 457 when N_Slice => 458 Expand_N_Slice (N); 459 460 when N_Subtype_Indication => 461 Expand_N_Subtype_Indication (N); 462 463 when N_Subprogram_Body => 464 Expand_N_Subprogram_Body (N); 465 466 when N_Subprogram_Body_Stub => 467 Expand_N_Subprogram_Body_Stub (N); 468 469 when N_Subprogram_Declaration => 470 Expand_N_Subprogram_Declaration (N); 471 472 when N_Task_Body => 473 Expand_N_Task_Body (N); 474 475 when N_Task_Type_Declaration => 476 Expand_N_Task_Type_Declaration (N); 477 478 when N_Timed_Entry_Call => 479 Expand_N_Timed_Entry_Call (N); 480 481 when N_Type_Conversion => 482 Expand_N_Type_Conversion (N); 483 484 when N_Unchecked_Expression => 485 Expand_N_Unchecked_Expression (N); 486 487 when N_Unchecked_Type_Conversion => 488 Expand_N_Unchecked_Type_Conversion (N); 489 490 when N_Variant_Part => 491 Expand_N_Variant_Part (N); 492 493 -- For all other node kinds, no expansion activity required 494 495 when others => 496 null; 497 end case; 498 499 exception 500 when RE_Not_Available => 501 goto Leave; 502 end; 503 504 -- Set result as analyzed and then do a possible transient wrap. The 505 -- transient wrap must be done after the Analyzed flag is set on, so 506 -- that we do not get a recursive attempt to expand the node N. 507 508 Set_Analyzed (N); 509 510 -- Deal with transient scopes 511 512 if Scope_Is_Transient and then N = Node_To_Be_Wrapped then 513 case Nkind (N) is 514 when N_Procedure_Call_Statement 515 | N_Statement_Other_Than_Procedure_Call 516 => 517 Wrap_Transient_Statement (N); 518 519 when N_Object_Declaration 520 | N_Object_Renaming_Declaration 521 | N_Subtype_Declaration 522 => 523 Wrap_Transient_Declaration (N); 524 525 when others => 526 Wrap_Transient_Expression (N); 527 end case; 528 end if; 529 530 Debug_A_Exit ("expanding ", N, " (done)"); 531 end if; 532 533 <<Leave>> 534 Restore_Ghost_Region (Saved_GM, Saved_IGR); 535 end Expand; 536 537 --------------------------- 538 -- Expander_Mode_Restore -- 539 --------------------------- 540 541 procedure Expander_Mode_Restore is 542 begin 543 -- Not active (has no effect) in ASIS and GNATprove modes (see comments 544 -- in spec of Expander_Mode_Save_And_Set). 545 546 if ASIS_Mode or GNATprove_Mode then 547 return; 548 end if; 549 550 -- Otherwise restore the flag 551 552 Expander_Active := Expander_Flags.Table (Expander_Flags.Last); 553 Expander_Flags.Decrement_Last; 554 555 -- Keep expander off if serious errors detected. In this case we do not 556 -- need expansion, and continued expansion may cause cascaded errors or 557 -- compiler bombs. 558 559 if Serious_Errors_Detected /= 0 then 560 Expander_Active := False; 561 end if; 562 end Expander_Mode_Restore; 563 564 -------------------------------- 565 -- Expander_Mode_Save_And_Set -- 566 -------------------------------- 567 568 procedure Expander_Mode_Save_And_Set (Status : Boolean) is 569 begin 570 -- Not active (has no effect) in ASIS and GNATprove modes (see comments 571 -- in spec of Expander_Mode_Save_And_Set). 572 573 if ASIS_Mode or GNATprove_Mode then 574 return; 575 end if; 576 577 -- Otherwise save and set the flag 578 579 Expander_Flags.Increment_Last; 580 Expander_Flags.Table (Expander_Flags.Last) := Expander_Active; 581 Expander_Active := Status; 582 end Expander_Mode_Save_And_Set; 583 584end Expander; 585